Surface Area

Interview

Time limit1sMemory limit512 MB

Summary
Given a grid of cube stack heights, compute the total surface area of the resulting 3D figure, including the top, bottom, and exposed side faces.
Level

Medium4 of 10

Topics
Implementation, Math, Array, Simulation
Solved
No attempts yet

Problem

There is a sheet of paper of size N×M, divided into cells of size 1×1. A cube of size 1×1×1 is placed on each cell to form a three-dimensional figure.

Given the number of cubes placed on each cell of the paper, write a program that computes the surface area of this figure.

The figure above shows cubes placed on a 3×3 sheet of paper, and its surface area is 60.

Input

The first line gives the size of the paper, N and M. From the second line, N lines give the number of cubes placed on each cell of the paper.

Output

On the first line, print the surface area of the figure.

Constraints

  • 1 ≤ N, M ≤ 100
  • 1 ≤ number of cubes on one cell ≤ 100

Examples2

  1. Example 1

    Input
    1 1
1
    Expected output
    6

  2. Example 2

    Input
    3 3
1 3 4
2 2 3
1 2 4
    Expected output
    60